A sword, a bokken even a piece of wood (which you could use here) is an inert piece of material that provides a hard edge. What makes it potentially dangerous is the way we use the body to transfer mass which becomes kinetic energy that's amplified when it travels to a thin, hard 'edge'. Training with weapons has a distinct physical and mental component which come together the moment you move. Bladesong is a workout that delivers on all fronts. Let your inhibitions loose and your imagination free. Allow your body to move in tune with your mind. Stay away from breakables.
Extra Credit: 1 minute rest between sets.